It will be useful if high-precision and high-speed detection of extremely feeble light and radiation is made possible. For example, it is under study to make use of a so-called DNA chip, on which part of genes are arranged in large number, for disease treatment and prevention by a method of combining (hybridization) genes in an analyte collected from a human body and having a fluorescent material added thereto and the genes on the DNA chip, thereby examining which one of the genes on the DNA chip is hybridized. The hybridized gene on the DNA chip is specified by the detection of fluorescence originating from the fluorescent material added in the analyte.
Further, if a so-called reflected X-ray imaging device that detects a backscattered X-ray emitted to a substance to convert it to an image can be realized, nondestructive inspection using an X-ray can be conducted easily on a surface portion of a large structure such as wings of an airplane, and an inspection device can be downsized.
Moreover, if a night vision camera with enhanced sensitivity can be produced, various observations which have been difficult due to the influence of light and observation of the influence of light and so on can be easily conducted.
Conventionally, in detecting feeble light, after light (photons) is converted to electrons, the electrons are amplified by a secondary electron multiplier such as a photomultiplier tube to be detected. Further, a feeble radiation ray such as an X-ray or a γ ray has been detected in such a manner that the radiation ray is made incident on a scintillator to be converted to light and this light is further converted to electrons by a photomultiplier tube or the like.
Further, in detecting feeble light two dimensionally, a device called a microchannel plate is available. This is configured such that several millions of very thin glass capillaries each being about 6 μm to about 25 μm in diameter and about 0.24 mm to about 1.0 mm in length are bundled and finished in a thin plate shape, and each of the capillaries (channels) arranged in a thickness direction functions as an independent secondary electron multiplier and the entire unit of the capillaries form a secondary electron multiplier. This microchannel plate (hereinafter, referred to as an MCP) has a high-speed property, and a high-gain property, and exhibits an excellent pulse-height distribution property according to the intensity of light to have a two-dimensional detecting function.
When this MCP is utilized, a photoelectric surface is disposed on a light incident part and photons are converted to electrons, which are then made incident on the capillaries of the MCP. The electrons incident on the capillaries are accelerated by a direct-current voltage of about 2000 V applied on both sides of the capillaries and collide with tube walls of the capillaries, so that the number thereof is increased about 104 to 1012 times. The performance of a device using the MCP is determined by how an electronic pulse group thus amplified and outputted is read.
Conventionally, in order to read electronic pulses (electrons whose number is increased) outputted from an MCP, a typical method is such that a fluorescent surface is disposed on an output side of the MCP, and after the electron pulses are once converted to light, this light is photographed by a CCD camera.
However, in the above-mentioned conventional method of converting electronic pulses amplified by the MCP to light and photographing this light by the CCD camera, it is practically difficult to detect extremely feeble light such as fluorescence emitted by a DNA chip and a feeble radiation such as a backscattered X-ray since electrons are scarcely incident on the capillaries of the MCP and a pulse width of the electronic pulses outputted from the MCP is extremely short such as less than nanoseconds and therefore, a noise signal is larger than a detection signal.
The present invention is made in order to solve the above-mentioned drawbacks of the prior art, and an object thereof is to enable the two-dimensional detection of feeble light and radiation ray.